Brans of the roller-milled barley fractions rich in polyphenols and health-promoting lipophilic molecules

Abstract

Three different roller-milled fractions namely bran, middlings, and flour of five commonly grown Irish barley varieties were investigated for the presence of β-glucan, polyphenols, and health-promoting lipophilic molecules. β-glucan was predominantly located in barley middlings. Polyphenols, as indicated by total phenolic content and the antioxidant activities, were abundant in the outermost bran fractions of barley. Similarly the health-promoting lipophilic molecules including phytosterols, unsaturated fatty acids, and tocols were most abundant in the barley bran fraction. However, the distribution of individual polyphenols and lipophilic compounds varied within the grain; for example ferulic acid and procyainidin C were not detected in flour fraction. Principal component analysis (PCA) clearly indicated a higher distribution of most bioactive molecules in bran as compared to middlings and flour fractions. The PCA also established possible correlations between the five barley varieties and their fractions based on their clustering in the plot.